Microsoft plans to deliver 11 security updates next week to patch 25 vulnerabilities in Windows, Office and Exchange.

In its monthly advance notification, Microsoft spelled out next week's double-digit Patch Tuesday, which is entirely in line with company's pattern of alternating large- and small-sized updates.

Five of the impending updates were labelled 'critical' by Microsoft, the top threat ranking in its four-step scoring system. Another five were labelled 'Important', the second-highest next rating, while the last was marked 'Moderate'.

Windows 7 will receive four of the 11 updates. Also planned are patches for Publisher, the desktop publishing program included with some editions of Microsoft Office, and for Exchange, the widely-used email server.

Microsoft will not patch a vulnerability in IE confirmed by the company in early February. Hackers can use the bug to attack IE on Windows XP, or IE7 or IE8 on other versions of Windows if the browser's Protected Mode has been disabled, Microsoft said then.

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